Question

Error

System.NullReferenceException: 'Object reference not set to an instance of an object.'

System.Web.Mvc.WebViewPage<TModel>.Model.get returned null.

I’m try to create a quiz app where user can give quiz exam and from admin side they can create a quiz. I used a .NET framework for it, Thanks For your response

My View

@model QuizApp.Models.tbl_questions

@{
    Layout = null;
}

<!DOCTYPE html>

<body>
    @using (Html.BeginForm())
    {
        @Html.AntiForgeryToken()

        <div class="form-horizontal">
            <h4>Quiz Start</h4>
            @if (@ViewBag.Message != null)
            {
                <div class="alert alert-danger">
                    <strong>Error!</strong> @ViewBag.Message
                </div>
            }
            <hr />
            @Html.ValidationSummary(true, "", new { @class = "text-danger" })
            <div class="form-group">
                @Html.LabelFor(model => model.q_text, htmlAttributes: new { @class = "control-label col-md-2" })
                <div class="col-md-10">
                    @Html.DisplayFor(model => model.q_text, new { htmlAttributes = new { @class = "form-control" } })
                    @Html.ValidationMessageFor(model => model.q_text, "", new { @class = "text-danger" })
                </div>
            </div>

            <div class="form-group">
                @Html.LabelFor(model => model.QA, htmlAttributes: new { @class = "control-label col-md-2" })
                <div class="col-md-10">
                    <span> @Html.RadioButtonFor(model => model.QA, new { htmlAttributes = new { @class = "form-control" } }) @Model.QA </span>
                    @Html.ValidationMessageFor(model => model.QA, "", new { @class = "text-danger" })
                </div>
            </div>

            <div class="form-group">
                @Html.LabelFor(model => model.QB, htmlAttributes: new { @class = "control-label col-md-2" })
                <div class="col-md-10">
                    <span> @Html.RadioButtonFor(model => model.QB, new { htmlAttributes = new { @class = "form-control" } }) @Model.QB </span>
                    @Html.ValidationMessageFor(model => model.QB, "", new { @class = "text-danger" })
                </div>
            </div>

            <div class="form-group">
                <div class="col-md-offset-2 col-md-10">
                    <input type="submit" value="Create" class="btn btn-success" />
                </div>
            </div>
        </div>
    }

    <div>
        @Html.ActionLink("Back to List", "Index")
    </div>
</body>
</html>

Error comes on this line }) @Model.QA

Controller

public ActionResult StartQuiz()
{
    tbl_questions q = null;

    if (TempData["q_id"] != null)
    {
        int examId = Convert.ToInt32(TempData["examid"]);
        q = db.tbl_questions.FirstOrDefault(x => x.q_fk_cat_id == examId);
        //tbl_questions q = db.tbl_questions.Where(x => x.q_fk_cat_id == examId ).SingleOrDefault();
    }
    else
    {
        ViewBag.Message = "No Questions Found!";
    }
    return View(q);
}

when i login and try to enter in quiz its return null reference When there is a data in database

i try to modify this line

q = db.tbl_questions.First(x => x.q_fk_cat_id == examId);tbl_questions q = db.tbl_questions.Where(x => x.q_fk_cat_id == examId ).SingleOrDefault();

to this

q = db.tbl_questions.FirstOrDefaul(x => x.q_fk_cat_id == examId);

but its not work, it still gives error same, i don’t know why it takes null reference when there is a already 4 data in the database is available.

getting error when try fetch data, System.NullReferenceException: ‘Object reference not set to an instance of an object.’

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